[Adonis]

-Attack from outer species

-World Ending Catasrophe ABOUT to happen...I.e the sun diminishing it's power. This one would be over time though. So if Earth knows the star will dwindle and die say in the next 100-200 years, we as a race, not nation (s) would bring about the building of a ship to seek life on another planet quickly. While that ship(s) seek(s) We would also build a "massive carrier" (Noahs Ark) to transport the lucky thousands (1 percenters)

a. This also includes the loss, or need of any element needed for life much like the already mentioned Planetary boundaries I assume.

b. Now that I think of it, there would actually be more looting then togetherness considering the other 99% of the population, but still, china, USA and other wealthy nations would pull there resources to build Noah's Ark.



I think that is it though. Literally